Polyethylene stabilized with 2,6-di (1-methyl heptadecyl)-4-alkyl phenol

ABSTRACT

This invention relates to a composition of matter consisting of vulcanizable polyethylene which is protected from oxidative deterioration over a period of time. More specifically this invention is directed to a composition of polyethylene crosslinked by a bisperoxide in the presence of an antioxidant such as 2,6-di(1-methyl heptadecyl)-4-alkyl phenol.

United States Patent 1 Rowland et a1.

[ POLYETHYLENE STABILIZED WITH 2,6-DI l-METHYL HEPTADECYL )-4-ALKYLPHENOL [75] Inventors: Bobby A. Rowland; Stanley L. Tate,

both of Carrollton, Ga.

[73] Assignee: Southwire Company, Carrollton,

[22] Filed: Dec. 29, 1971 [21] Appl. No.: 213,546

[52] US. Cl. 117/232, 161/216, 260/41 R, 260/41 A, 260/41 B, 260/45.95,260/94.9 GA [51] Int. Cl. B44d l/34, C08f 45/58 [58] Field of Search260/41, 94.9 GA,

[56] References Cited UNITED STATES PATENTS 3,335,124 8/1967 Larsen260/94.9

[ Nov. 20, 1973 3,118,866 l/1964 Gregorian 260/94.9 3,454,525 7/1969Tholstrup 260/45.85 2,916,481 12/1959 Gilmont 260/94.9 3,017,376 1/1962Baiford et al 260/23 Primary ExaminerMorris Liebman Assistant ExaminerJ.I-l. Derrington Att0meyVan C. Wilks et a1.

[5 7 ABSTRACT 50 Claims, No Drawings POLYETIIYLENE STABILIZED WITH2,6-DI (l-METIIYL HEPTADECYL)-4-ALKYL PI-IENOL DESCRIPTION OF THE PRIORART Polyethylene cross-linked by a bisperoxide, such as a, a, a,a'-tetramethyl isophthalyl di-t-butyl bisperoxide, was disclosed in U.S.Pat. No. Re25,94l. U.S. Pat. No. 2,888,424 discloses cross-linkedpolyethylene filled with silica, carbon black, alumina or calciumsilicate. Chemically crosslinked polyethylene stabilized withpolymerized trimethyl quinoline was disclosed in U.S. Pat. No.3,296,189.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Peroxide vulcanized orcross-linked polyethylene possesses properties such as temperaturestability, solvent resistance, and tensile strength which enable it tobe used in many applications where thermoplastic polyethylene would beunsatisfactory. However, extreme care must be exercised in compoundingthe composition to avoid excess peroxide since the same properties whichmake peroxides cross-linking agents will bring about oxidationdeterioration in the final product.

The solution to the problem of oxidative deterioration in thepolyethylene caused by the presence of peroxide would appear to be theaddition of antioxidants such as those developed in rubber technology.However, antioxidants are substances which will selectively combine withoxygen thereby converting oxygen from a state in which it can promoteoxidation of an important component of a composition to one in which itcombines with a minor component which holds it in a state where it cando no further harm. It would be predicted that antioxidants wouldcombine with peroxides, or decomposition products thereof, to cancel outboth the cross-linking activity of the peroxide and the antioxidantactivity, and experimental evidence has shown that this is what happensin the case of most antioxidants.

The present invention has as one of its objects to provide a peroxidecross-linkable polyethylene composition which is stabilized againstoxidative deterioration.

Another object of the invention is to provide a peroxide cross-linkedpolyethylene composition which in cludes an antioxidant.

Briefly stated, in accordance with one of its embodiments, thisinvention is directed to a curable composition comprising polyethylene,a bisperoxide having the general formula:

where R is a member of the group consisting of methyl and phenyl, and astabilizer consisting of 2,6-di( 1- methyl heptadecyl)-4-alkyl phenol.

In accordance with this invention, it has been discovw d atlj-qfl lrnsthyl hsmad x!): .kx Phenol where R is a lower alkyl containing fromone to four carbon atoms, will act as an antioxidant for peroxidecross-linked polyethylene without significantly interfering with thecross-linking activity of the peroxide. When 2,6-di( l-methylheptadecyl)-4-alkyl phenol is present in proportions of less than about4.0 percent based on the weight of polyethylene present, there isfrequently an enhancement of the properties of the product. For example,the addition of 0.5 parts of 2,6- di(l-methyl heptadecyl)-4-alkyl phenolper parts of polyethylene produced a product having a tensile strengthof about 2,700 pounds per square inch versus about 2,600 pounds persquare inch for a control sample in which 2,6-di(l-methylheptadecyl)-4-alkyl phenol was absent.

In the antioxidant covered by Formula II, R can represent methyl, ethyl,ethylene, propyl, 2-propyl, propylene, n-butyl, l-butylene, secondarybutylene, 2- butylene, tertiary butyl, and isobutylene. Preferably Rrepresents methyl, ethyl, propyl or n-butyl. The most preferredembodiment of this invention is where R represents methyl or ethyl.

If the antioxidant of this invention is present in excessiveproportions, it has an inhibitory effect upon the activity of thecross-linking peroxide, though this inhibitory effect is not so great asthat produced by equivalent quantities of other antioxidants common topolyethylene technology. A preferred range of 2,6-di(lmethylheptadecyl)-4-alkyl phenol is from about 0.01 percent to about 4.0precent by weight of the polyethylene present.

The 2,6-di(1-methyl heptadecyl)-4-alkyl phenol axtioxidants of thisinvention are operable both in filled and unfilled systems. Silica,carbon black, alumina, calcium silicate and the like are satisfactoryfiller materials usable in conjunction with the antioxidants of theinvention.

The present invention is directed to a conposition which is suitable forboth molding and extrusion. Its compounding is conventional in allrespects. One method of handling is to introduce the componentsincluding the peroxide and 2,6-di( l-methyl heptadecyl)- 4-alkyl phenolto a Ferrell continuous mixer maintained at a temperature slightly abovethe melting temperature of the polyethylene used. This step is followedby a milling operation which further works the composition prior to ashredding and dicing step. The diced material may then be stored untilthe final processing. It is preferable that the final processing? takeplace within a relatively small number of days.

The bisperoxides of this invention are characterized as substantiallydecomposing at temperatures in excess of C and having the generalformula:

Two of the preferred bisperoxides used as cross-linking agents in thisinvention are a, a, a, a'-tetramethyl isophthalyl di-t-butylbisperoxide, a compound of the mglm CHa and a, a, a, a'-tetramethylisophthalyl dicumyl bisperoxide, a compound of the formula:

in addition, these peroxides may contain inorganic groups, such ashalogens, nitro groups, etc., for example, chlorophenyl, bormophenyl,nitrophenyl, etc.

While the proportion of peroxide used depends upon the final propertiessought in the cured material, a range of from about 0.1 percent to aboutpercent by weight of the polyethylene present satisfies mostrequirements, and the usual proportion is of the order of from about 0.5percent to about 4.0 percent. Since the peroxide is more costly thanpolyethylene and any fillers which might be used, economy dictates usingthe minimum peroxide which will provide the properties desired in thecured material.

The invention applies generally to polyethylene whether it is made bythe conventional high pressure process or the low pressure catalyticprocess. While polyethylene is the most important component of any ofthe compositions of this invention and the proportions of peroxide and2,6-di(l-methyl heptadecyl)-4- alkyl phenol are recited in terms of thepolyethylene present-other components may also be present. For example,filler materials such as those previously specified herein may bepresent from about 0.5 percent to about 400 percent by weight ofpolyethylene present.

This invention applied to copolymers of ethylene and other polymerizablematerials such as propylene, ethyl acrylate, vinyl acetate and butylene.The copolymer materials may be present in proportions from less thanabout l percent to more than about 50 percent by weight of thepolyethylene present. The invention likewise applies to mixtures ofpolyethylene and other polymers such as polyvinyl chloride,organopolysiloxanes, polymeric methyl acrylate, copolymers of butadieneand styrene, copolymers of butadiene and acrylonitrile, neoprene,polystyrene, various natural rubbers, etc.

The stabilized cross-like compositions of this invention have a varietyof uses. One advantageous use is in insulation coatings for electricalconductors. An insulated electrical conductor can be formed by coatingan electrically conductive material with one or more of the compositionsof this invention. The compositions can be applied by any of theindustry accepted methods of applying a polymerized insulation coatingto an electrical conductor.

An advantageous method of coating an electrical conductor with one ormore of the compositions of this inventionis to extrude the composition,at a tempera ture of from about F, onto an electrical conductor; curethe coated electrical conductor by passing it through a continuousvulcanization tube which has an operating temperature of from about 350Fto 480F; and cool the cured, coated electrical conductor.

Below are several examples, which are intended to be illustrative ratherthan limiting, of the compositions of this invention.

EXAMPLE 1 Dylan WPD 205 polyethylene (100 parts) and Thermax carbonblack (40 parts) were worked on a mill at 220F and 0.5 parts2,6-di(l-methyl heptadecyl)-4- methyl phenol and two parts aa, a,a'-tetramethyl isophthalyl di-t-butyl bisperoxide were added. Thecomposition was molded in a press for 7 minutes at 350F. A dumbellsample one-fourth inch wide and 0.07 inch thick was then cut fortesting. The tensile strength of this sample was 2,375 p.s.i. and itselongation 395 percent. After 168 hours in an air oven at 121C thetensile strength was 2,400 p.s.i. and elongation 405 percent.

A control sample of the same conposition except that the 2,6-di(l-methylheptadecyl)-4-methyl phenol was omitted had a initial tensile strengthof 2,520 p.s.i. and elongation 340 percent. After 72 hours in an airoven at 121C this sample became brittle and remained in this statethereafter.

EXAMPLE 2 A sample was prepared in the manner set forth in Example 1except that 0.5 parts 2,6-di( l-methyl heptadecyl)-4-ethyl phenol waspresent instead of 0.5 parts 2,6-di( l-methyl heptadecyl)-4-methylphenol. The initial tensile strength of the test specimen as 2,405p.s.i. and the elongation 390 percent. After 168 hours in an air oven at121C the tensile strength was 2,450 p.s.i. and elongation 390 percent.

EXAMPLE 3 A control sample consisting of 100 parts polyethylene, 100parts carbon black, and 2.25 parts a, a, a, a'-tetramethyl isophthalyldi-t-butyl bisperoxide underwent a reduction in tensile strength from2,700 p.s.i. to 1,800 p.s.i. after being aged for 168 hours at 121C.Material of the same conposition with 0.50 parts 2,6-di( l-rnethylheptadecyl)-4-methyl phenol added gave a product having an intialtensile strength of 2,455 p.s.i. which increased to 2,495 p.s.i. afteran aging treatment for 168 hours at 121C. The original elongation of thecontrol was percent. After 168 hours at 121C this declined to 25percent. The original elongation of the material having the samecomposition with 0.50 parts 2,6-di( l-methyl heptadecyl)-4-methyl phenolwas 395 percent. After aging for 168 hours at 121C the elongationincreased to 410 percent.

EXAMPLE 4 A sample prepared in the manner set forth in Example 1 exceptthat 1.5 parts 2,6-di(1-methyl heptadecyl)-4-methyl phenol were presenthad an initial tensile strength of 2,410 p.s.i. and an elongation of 400percent. After 168 hours in an air oven at 121C, the sample had atensile strength of 2,425 p.s.i. and an elongation of 415 percent.

EXAMPLE 5 EXAMPLE 6 A sample was prepared in the manner set forth inExample 1, except that 0.5 parts, 1,2-dihydro-2,2,4- trimethylquinoline(an industry accepted antioxidant for use in polyethylene production)was present instead of 0.5 parts 2,6-di(1-methyl heptadecyl)-4-methylphenol. The test results of the sample before aging were: tensilestrength 2,3 80 p.s.i. and elongation 340 percent; after aging in themanner set forth in Example 1 the tensile strength was 2,330 p.s.i. andelongation 325 percent.

EXAMPLE 7 A sample was prepared in the manner set forth in Example 1except that two parts a, a, a, a'-tetramethyl isophthalyl di-cumylbisperoxide were added instead of two parts a, a, -tetramethylisophthalyl di-t-butyl bisperoxide. The tensile strength of the testspecimen was 2,370 p.s.i. and its elongation 395 percent. After 168hours in an air oven at 121C the tensile strength was 2,330 p.s.i. andelongation 400 percent.

A control sample of the same composition except that the 2,6-di(1-methylheptadecyl)-4-methyl phenol was omitted had an initial tensile strengthof 2,390 p.s.i. and elongation 340 percent. After 72 hours in an airoven at 121C this sample became brittle and remained in this statethereafter.

EXAMPLE 8 A sample was prepared in the manner set foth for Example 7except that 0.5 parts 2,6-di(1-methyl heptadecyl)-4-ethyl phenol waspresent instead of 0.5 parts 2,6-di( l-methyl heptadecyl)'-4-methylphenol. The initial tensile strength of the test specimen was 2,420p.s.i. and the elongation 400 percent. After 168 hours in an air oven at121C the tensile strength was 2,440 p.s.i. and elongation 415 percent.

EXAMPLE 9 A control sample consisting of 100 parts polyethylene, 100parts carbon black, and 2.25 parts a, a, a, a'-tetramethyl isophthalyldi-cumyl bisperoxide underwent a reduction in tensile strength from2,680 p.s.i. to 1,810 p.s.i. after being aged for 168 hours at 121c.Material of the same composition with 0.50 parts 2,6- di(1-methylheptadecyl)-4-methyl phenol added gave a product having an initialtensile strength of 2,460 p.s.i. which increased to 2,510 p.s.i after anaging treatment for 168 hours at 121C. The original elongation of thecontrol was 190 percent. After 168 hours at 121C this declined to 40percent. The original elongation of the material having the samecomposition with 0.50 parts 2,5-di(1-methyl heptadecyl)-4-methyl phenolwas 395 percent. After aging for 168 hours at 121C the elongationincreased to 410 percent.

EXAMPLE 10 A sample prepared in the manner set forth in Example 7 exceptthat 1.5 parts 2,6-di( l-methyl heptadecyl)-4-methyl phenol were presenthad an initial tensile strength 2,395 p.s.i. and an elongation of 370percent. After 168 hours in an air oven at 121C the sample had a tensilestrength of 2,410 p.s.i. and an elongation of 390 percent.

EXAMPLE 1 1 A sample was prepared in the manner set foth in Example 7.The sample was divided into two parts and tested as in Example 7. Theinitial tensile strength of this sample was 2,370 p.s.i. and itselongation 395 percent. One sample was put in an air oven for 168 hoursat 121C, the resulting tensile strength was 2,360 p.s.i. and elongation410 percent. The other sample was oxygen-bomb aged in an oven at C and300 p.s.i. for 168 hours, the resulting tensile strength was 2,300p.s.i. and elongation 385 percent.

It should be understood that the air oven tests listed in the aboveexamples are very rigorous. For example, correlation studies have shownthat-a sample which was reduced to 30 percent elongation after 5 hoursat 210C, for 6 days at 180C, or 23 days at 165C or days at 150C wouldhave an expected service life of 15 years under conditions of continuousservice at 120C. All of the samples in the above examples whichcontained 2,6-di( l-methyl heptadecyl)-4-alkyl phenol would be expectedto exceed this service life by a considerable margin.

While the invention has been described in detail with particularreference to certain preferred embodiments, it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention as hereinbefore described and defined in the appendedclaims.

What is claimed is:

l. A curable composition of matter comprising:

a. normally solid polyethylene:

b. from about 0.1 percent to about 10 percent by weight of thepolyethylene present of a bisperoxide of the formula:

where R is selected from the group consisting of methyl and phenyl, saidbisperoxide substantially decomposing at temperatures in excess of C,thereby crosslinking the polyethylene of said composition; and

c. from about 0.01 percent to about 4.0 percent by weight of thepolyethylene present of the antioxidant 2,6-di( l-methylheptadecyl)-4-alkyl phenol. 2. A cured composition according to claim 1,having been cured at a temperature in excess of 130C.

3. A composition according to claim 1, wherein the bisperoxide is a, a,a, a-tetramethyl isophthalyl di-tbutyl bisperoxide.

4. A cured composition according to claim 3, having been cured at atemperature in excess of 130C.

5. A composition according to claim 1, wherein the bisperoxide is a, a,a, a'-tetramethyl isophthalyl dicumyl bisperoxide.

6. A cured composition according to claim 5, having been cured at atemperature in excess of 130C.

7. The composition of claim 1, wherein the antioxidant is 2,6-di(l-methyl heptadecyl)-4-methyl phenol.

8. A cured composition according to claim 7, having been cured at atemperature in excess of 130C.

9. A composition according to claim 7, wherein the bisperoxide is a, a,a, oz-tetramethyl isophthalyl di-tbutyl bisperoxide.

10. A cured composition according to claim 9, having been cured at atemperature in excess of 130C.

11. A composition according to claim 7, wherein the bisperoxide is a, a,a, oz'-tetramethyl isophthalyl dicumyl bisperoxide.

12. A cured composition according to claim 11, having been cured at atemperature in excess of 130C.

13. The composition of claim 1, wherein the antioxidant is 2,6-di(l-methyl heptadecyl)-4-ethyl phenol.

14. A cured composition according to claim 13, having been cured at atemperature in excess of 130C.

15. A composition according to claim 13, wherein, the bisperoxide is a,a, a, a'-tetramethyl isophthalyl di-t-butyl bisperoxide.

I 16. A cured composition according to claim 15, having been cured at atemperature in excess of 130C.

17. A composition according to claim 13, wherein the bisperoxide is a,a, a, a-tetramethyl isophthalyl di-cumyl bisperoxide.

18. A cured composition of matter according to claim 17, having beencured at a temperature in excess of 130C.

19. An electrical conductor having an insulation coating of thecomposition of claim 1.

20. A curable composition comprising:

a. a member selected from the group consisting of polyethylene, blendsof polyethylene and other polymers, copolymers of ethylene and otherpolymerizable materials;

b. from about 0.1 percent to about 10 percent by weight of thepolymerizable material present of a bisperoxide of the formula:

where R is selected from the group consisting of methyl and phenyl, saidbisperoxide substantially decomposing at temperatures in excess of 130C,thereby crosslinking the polymerizable material of said composition; and

c. from about 0.01 percent to about 4.0 percent by weight of thepolymerizable material present of the antioxidant 2,6-di( l-methylheptadecyl)- 4-alkyl phenol. 21. An electrical conductor having aninsulation coating of the composition of claim 20.

22. The process which comprises admixing normally solid poylethylene;from about 0.1 percent to about 10 percent by weight of the polyethylenepresent of bisperoxide of the formula:

where R is selected from the group consisting of methyl and phenyl; andfrom about 0.01 percent to about 4.0 percent by weight of thepolyethylene present of the antioxidant 2,6-di( l-methylheptadecyl)-4-aklyl phenol; and heating said admixture to effectcrosslinking of the polyethylene.

23. The process which comprises admixing a member selected from thegroup consisting of polyethylene, blends of polyethylene and otherpolymers, and copolymers of ethylene and other polymerizable materials,from about 0.1 percent to about 10 percent by weight of thepolymerizable material present of a bisperoxide of the formula:

wherein R is selected from the group consisting of methyl and phenyl;and from about 0.01 percent to about 4.0 percent by weight of thepolymerizable material present of the antioxidant 2,6-di(1-methylheptadecyl)-4-alkyl phenol; and heating said admixture to effectcross-linking of said polymerizable material.

24. The method of making an electrical conductor having an insulationcoating of the composition of claim 1 which comprises:

a. extruding the composition, at a temperature of from about F to about340F, onto an electrical conductor;

b. curing the coated electrical conductor by passing through acontinuous vulcanization tube having an operating temperature of fromabout 350F to about 480F; and

c. cooling the cured, coated electrical conductor.

25. The method of making an electrical conductor having an insulationcoating of the composition of claim 20, which comprises:

a. extruding the composition, at a temperature of from about 170F toabout 340F, onto an electrical conductor;

b. curing the coated electrical conductor by passing through acontinuous vulcanization tube having an operating temperature of fromabout 350F to about 480F; and

c. cooling the cured, coated electrical conductor.

26. A curable composition of matter comprising:

a. normally solid polyethylene;

b. from about 0.1 percent to about 10 percent by weight of thepolyethylene present of a bisperoxide of the formula:

where R is selected from the group consisting of methyl and phenyl, saidbisperoxide substantially decomposing at temperatures in excess of 130C,thereby crosslinking the polyethylene of said composition.

c. from about 0.5 percent to about 400 percent by weight of thepolyethylene present of a filler selected from the group consisting ofsilica, carbon black, alumina, and calcium silicate; and

d. from about 0.01 percent to about 4.0 percent by weight of thepolyethylene present of the antioxidant 2,6-di( l-methylheptadecyl)-4-alkyl phenol.

27. A cured composition according to claim 26 having been cured at atemperature in excess of 130C.

28. A composition according to claim 26 wherein the bisperoxide is a, a,a, a'-tetramethyl isophthalyl di-tbutyl bisperoxide.

29. A cured composition according to claim 28, having been cured at atemperature in excess of 130C.

30. A composition according to claim 26, wherein the bisperoxide is aa,a, a-tetramethyl isophthalyl dicumyl bisperoxide.

31. A cured composition according to claim 30, having been cured at atemperature in excess of 130C.

32. The composition of claim 26, wherein the antioxidant is 2,6-di(l-methyl heptadecyl)-4-methyl phenol.

33. A cured composition according to claim 32, having been cured at atemperature in excess of 130C.

34. A composition according to claim 32, wherein the bisperoxide is a,a, a, a'-tetramethyl isophthalyl di-t-butyl bisperoxide.

35. A cured composition according to claim 34, having been cured at atemperature in excess of 130C.

36. A composition according to claim 32, wherein the bisperoxide is a,a, a, a'-tetramethyl isophthalyl di-cumyl bisperoxide.

37. A cured composition according to claim 36, having been cured at atemperature in excess of 130C.

38. The composition of claim 26, wherein the antioxidant is 2,6-di(l-methyl heptadecyl)-4-ethyl phenol.

39. A cured composition according to claim 38, having been cured at atemperature in excess of 130C.

40. A composition according to claim 38, wherein, the bisperoxide is a,a, a, a'-tetramethyl isophthalyl di-t-butyl bisperoxide.

41. A cured composition according to claim 40, having been cured at atemperature in excess of 130C.

42. A composition according to claim 38, wherein the bisperoxide is a,a, a, a'-tetramethyl isophthalyl di-cumyl bisperoxide.

43. A cured composition of matter according to claim 42, having beencured at a temperature in excess of 130C.

44. An electrical conductor having an insulation coating of thecomposition of claim 26.

45. A curable composition comprising:

a. a member selected from the group consisting of polyethylene, blendsof polyethylene and other polymers, copolymers of ethylene and otherpolymerizable materials;

b. from about 0.01 percent to about 10 percent by weight of thepolymerizable material present of a bisperoxide of the formula:

where R is selected from the group consisting of methyl and phenyl, saidbisperoxide susbstantially decomposing at temperatures in excess of C,thereby crosslinking the polymerizable material of said composition;

c. from about 0.5 percent to about 400 percent by weight of thepolymerizable material present of a filler selected from the groupconsisting of silica, carbon black, alumina, and calcium silicate; and

d. from about 0.01 percent to about 4.0 percent by weight of thepolymerizable material present of the antioxidant 2,6-di(1-methylheptadecyl)-4-alkyl phenol.

46. An electrical conductor having an insulation coating of thecomposition of claim 45.

47. The process which comprises admixing normally solid polyethylene;from about 0.1 percent to about 10 percent by weight of the polyethylenepresent of bisperoxide of the forumla:

where R is selected from the group consisting of methyl and phenyl; fromabout 0.5 percent to about 400 percent by weight of the polyethylenepresent of a filler selected from the group consisting of silica, carbonblack, alumina, and calcium silicate; and from about 0.01 percent toabout 4.0 percent by weight of the polyethylene present of theantioxidant 2,6-di( l-methyl heptadecyl)- 4-alkyl phenol; and heatingsaid admixture to effect cross-linking of the polyethylene.

48. The process which comprises admixing a member selected from thegroup consisting of polyethylene, blends of polyethylene and otherpolymers, and copolymers of ethylene and other polymerizable materials;from about 0.10 percent to about 10 percent by weight of thepolymerizable material present of a bisperoxide of the formula:

wherein R is selected from the group consisting of methyl and phenyl;from about 0.5 percent to about 400 percent by weight of thepolymerizable material present of a filler selected from the groupconsisting of silica, carbon black, alumina, and calcium silicate; andfrom about 0.01 percent to about 4.0 percent by weight of thepolymerizable material present of the antioxidant 2,6-di(l-methylheptadecyl)-4-alkyl phenol; and heating said admixture to effectcross-linking of said polymerizable material. A

49. The method of making an electrical conductor having an insulationcoating of the composition of claim 26, which comprises;

a. extruding the composition, at a temperature of from about F to about340F, onto an electrical conductor;

b. curing the coated electrical conductor by passing through acontinuous vulcanization tube having an operating temperature of fromabout 350F to cal conductor; about 480F; and b. curing the coatedelectrical conductor by passing 0. cooling the cured, coated electricalconductor. through a continuous vulcanization tube having an 50. Themethod of making an electrical conductor operating temperature of fromabout 350F to having an insulation coating of the composition of 5 about480F; and claim 45, which comprises: c. cooling the cured, coatedelectrical conductor.

a. extruding the composition, at a temperature of from about 170F toabout 340F, onto an electri; r

2. A cured composition according to claim 1, having been cured at ateMperature in excess of 130*C.
 3. A composition according to claim 1,wherein the bisperoxide is Alpha , Alpha , Alpha '', Alpha''-tetramethyl isophthalyl di-t-butyl bisperoxide.
 4. A curedcomposition according to claim 3, having been cured at a temperature inexcess of 130*C.
 5. A composition according to claim 1, wherein thebisperoxide is Alpha , Alpha , Alpha '', Alpha ''-tetramethylisophthalyl di-cumyl bisperoxide.
 6. A cured composition according toclaim 5, having been cured at a temperature in excess of 130*C.
 7. Thecomposition of claim 1, wherein the antioxidant is 2,6-di(1-methylheptadecyl)-4-methyl phenol.
 8. A cured composition according to claim7, having been cured at a temperature in excess of 130*C.
 9. Acomposition according to claim 7, wherein the bisperoxide is Alpha ,Alpha , Alpha '', Alpha ''-tetramethyl isophthalyl di-t-butylbisperoxide.
 10. A cured composition according to claim 9, having beencured at a temperature in excess of 130*C.
 11. A composition accordingto claim 7, wherein the bisperoxide is Alpha , Alpha , Alpha '', Alpha''-tetramethyl isophthalyl di-cumyl bisperoxide.
 12. A cured compositionaccording to claim 11, having been cured at a temperature in excess of130*C.
 13. The composition of claim 1, wherein the antioxidant is2,6-di(1-methyl heptadecyl)-4-ethyl phenol.
 14. A cured compositionaccording to claim 13, having been cured at a temperature in excess of130*C.
 15. A composition according to claim 13, wherein, the bisperoxideis Alpha , Alpha , Alpha '', Alpha ''-tetramethyl isophthalyl di-t-butylbisperoxide.
 16. A cured composition according to claim 15, having beencured at a temperature in excess of 130*C.
 17. A composition accordingto claim 13, wherein the bisperoxide is Alpha , Alpha , Alpha '', Alpha''-tetramethyl isophthalyl di-cumyl bisperoxide.
 18. A cured compositionof matter according to claim 17, having been cured at a temperature inexcess of 130*C.
 19. An electrical conductor having an insulationcoating of the composition of claim
 1. 20. A curable compositioncomprising: a. a member selected from the group consisting ofpolyethylene, blends of polyethylene and other polymers, copolymers ofethylene and other polymerizable materials; b. from about 0.1 percent toabout 10 percent by weight of the polymerizable material present of abisperoxide of the formula:
 21. An electrical conductor having aninsulation coating of the composition of claim
 20. 22. The process whichcomprises admixing normally solid poylethylene; from about 0.1 percentto about 10 percent by weight of the polyethylene present of bisperoxideof the formula:
 23. The process which comprises admixing a memberselected from the group consisting of polyethylene, blends ofpolyethylene and other polymers, and copolymers of ethylene and otherpolymerizable materials, from about 0.1 percent to about 10 percent byweight of the polymerizable material present of a bisperoxide of theformula:
 24. The method of making an electrical conductor having aninsulation coating of the composition of claim 1 which comprises: a.extruding the composition, at a temperature of from about 170*F to about340*F, onto an electrical conductor; b. curing the coated electricalconductor by passing through a continuous vulcanization tube having anoperating temperature of from about 350*F to about 480*F; and c. coolingthe cured, coated electrical conductor.
 25. The method of making anelectrical conductor having an insulation coating of the composition ofclaim 20, which comprises: a. extruding the composition, at atemperature of from about 170*F to about 340*F, onto an electricalconductor; b. curing the coated electrical conductor by passing througha continuous vulcanization tube having an operating temperature of fromabout 350*F to about 480*F; and c. cooling the cured, coated electricalconductor.
 26. A curable composition of matter comprising: a. normallysolid polyethylene; b. from about 0.1 percent to about 10 percent byweight of the polyethylene present of a bisperoxide of the formula: 27.A cured composition according to claim 26 having been cured at atemperature in excess of 130*C.
 28. A composition according to claim 26wherein the bisperoxide is Alpha , Alpha , Alpha '', Alpha''-tetramethyl isophthalyl di-t-butyl bisperoxide.
 29. A curedcomposition according to claim 28, having been cured at a temperature inexcess of 130*C.
 30. A composition according to claim 26, wherein thebisperoxide is Alpha , Alpha '', Alpha ''-tetramethyl isophthalyldi-cumyl bisperoxide.
 31. A cured composition according to claim 30,having been cured at a temperature in excess of 130*C.
 32. Thecomposition of claim 26, wherein the antioxidant is 2,6-di(1-methylheptadecyl)-4-methyl phenol.
 33. A cured composition according to claim32, having been cured at a temperature in excess of 130*C.
 34. Acomposition according to claim 32, wherein the bisperoxide is Alpha ,Alpha , Alpha '', Alpha ''-tetramethyl isophthalyl di-t-butylbisperoxide.
 35. A cured composition according to claim 34, having beencured at a temperature in excess of 130*C.
 36. A composition accordingto claim 32, wherein the bisperoxide is Alpha , Alpha , Alpha '', Alpha''-tetramethyl isophthalyl di-cumyl bisperoxide.
 37. A cured compositionaccording to claim 36, having been cured at a temperature in excess of130*C.
 38. The composition of claim 26, wherein the antioxidant is2,6-di(1-methyl heptadecyl)-4-ethyl phenol.
 39. A cured compositionaccording to claim 38, having been cured at a temperature in excess of130*C.
 40. A composition according to claim 38, wherein, the bisperoxideis Alpha , Alpha , Alpha '', Alpha ''-tetramethyl isophthalyl di-t-butylbisperoxide.
 41. A cured composition according to claim 40, having beencured at a temperature in excess of 130*C.
 42. A cOmposition accordingto claim 38, wherein the bisperoxide is Alpha , Alpha , Alpha '', Alpha''-tetramethyl isophthalyl di-cumyl bisperoxide.
 43. A cured compositionof matter according to claim 42, having been cured at a temperature inexcess of 130*C.
 44. An electrical conductor having an insulationcoating of the composition of claim
 26. 45. A curable compositioncomprising: a. a member selected from the group consisting ofpolyethylene, blends of polyethylene and other polymers, copolymers ofethylene and other polymerizable materials; b. from about 0.01 percentto about 10 percent by weight of the polymerizable material present of abisperoxide of the formula:
 46. An electrical conductor having aninsulation coating of the composition of claim
 45. 47. The process whichcomprises admixing normally solid polyethylene; from about 0.1 percentto about 10 percent by weight of the polyethylene present of bisperoxideof the forumla:
 48. The process which comprises admixing a memberselected from the group consisting of polyethylene, blends ofpolyethylene and other polymers, and copolymers of ethylene and otherpolymerizable materials; from about 0.10 percent to about 10 percent byweight of the polymerizable material present of a bisperoxide of theformula:
 49. The method of making an electrical conductor having aninsulation coating of the composition of claim 26, which comprises; a.extruding the composition, at a temperature of from about 170*F to about340*F, onto an electrical conductor; b. curing the coated electricalconductor by passing through a continuous vulcanization tube having anoperating temperature of from about 350*F to about 480*F; and c. coolingthe cured, coated electrical conductor.
 50. The method of making anelectrical conductor having an insulation coating of the composition ofclaim 45, which comprises: a. extruding the composition, at atemperature of from about 170*F to about 340*F, onto an electricalconductor; b. curing the coated electrical conductor by passing througha continuous vulcanization tube having an operating temperature of fromabout 350*F to about 480*F; and c. cooling the cured, coated electricalconductor.